Metallurgy engineering

Controlled noise

A sandwich of steel sheets and a polymer form plates that absorb the vibrations of motors

EDUARDO CESARAdhesion of a polymer film to the steel sheets occurs in the furnace at 190o Celsius EDUARDO CESAR

Sound pollution is considered to be the third major cause of environmental pollution by the World Health Organization (WHO). The consequences of the excess of noise on the human ears translates into physical and psychological damages that install themselves gradually and affect the quality of life in large metropolises. Over the last few years, concern about acoustic control has resulted in requirements to be complied with by industries throughout the world before they can put their products on the market.

In Brazil, cars only leave the factory of they can produce maximum of 77 decibels of noise; motorbikes 80; trucks and buses 84. One of the ways in which the automobile industry has reached these goals is by covering the motor with material that absorbs noise and vibrations such as the sheeting VDS (Vibration Damping Steel), manufactured in the United States and in Japan, and which should be commercially launched in Brazil by the end of this year. The innovative technology was developed by the Brazilian company Fitafer Indústria e Comércio, in the town of Franco da Rocha, in the metropolitan area of São Paulo, through the support of the Small Business Innovation Research Program (PIPE), of FAPESP.

The seed of the Fitafer’s project which resulted in the VDS sheeting, composed of two steel sheets filled by a polymer in the form of a film, originated at the Technology Research Institute (IPT). In 1997, when the Foundation opened its doors to the first registrations for the PIPE program, the engineer Vicente Mazzarella, at that time technical director of the IPT, invited Francisco de Paula Assis Júnior, a retired engineer who had specialized in the areas of lamination and thermal treatments, with ten years of experience working for the Cosipa (Companhia Siderurgica Paulista – São Paulo Steelmaking Company), to coordinate the project.

“I found it interesting as it my work field. Brazil can only overcome this condition of an emerging country when it develops industrial technology”, says the engineer who graduated from the Polytechnic School of the University of São Paulo (USP) and is currently a professor at the Industrial Engineering School (FEI), of São Bernardo do Campo, and at the Mauá School of Engineering in the town of São Caetano do Sul. Mazzarella and Assis then looked for Fitafer, a producer of re-laminated steels, who had been performing with good results in the area and had an interest in diversifying their products.

Assis recounts that the starting point for their work was the VDS sheeting manufactured in the United States, used in the sump casing (part of the motor where the oil is stocked) of the combustion motors by MWM, an American company with a branch in Brazil. They supplied us with samples of the sheeting and we made an evaluation of the properties of the material. The big problem was to find an adequate polymer, since the company 3M, the supplier to the American manufacturer, refused to give us any samples.”

Stability and adherence
The next step was to select, with the help of the IPT, three candidate polymers to make up the VDS sheeting using national technology. Since this sheeting product must pass through a series of operations, the polymer cannot become detach itself from the system. Tests were done on adherence and stability up to temperatures of 150o Celsius. The experiments, which had never been done before in Brazil, were carried out at the institute with Polyvinyl Butyral (PVB) (PVB), polyethylene (PE) and polypropylene (PP).The steel used was SAE 1006, ceded by Fitafer. The tests at the laboratory phase resulted in the choice of PVB as the polymer that could best adhere to the steel sheets.

The second phase of the project, a pilot scale project, was carried out in part at Fitafer, with an oven and other accessories purchased with the financing by PIPE. In this phase, the PVB received various additives to better absorb the sound and vibrations and to guarantee its adherence to the steel sheets. “The results were considered very good and the polymer demonstrated itself to have good stability and adherence qualities”, says the project’s coordinator.The process of filling the sheets with the polymer is relatively simple.

The two steel sheets and the polymer film are leveled before entering the furnace, where they remain for close to an hour at a temperature of 190o Celsius. After the time necessary for the curing to occur, the sheet again passes through a leveling process and is ready to be used. “The biggest problem is that the assemblage remains well supported in the oven and that the curing of the polymer occurs, which signifies hardening and adherence, forming a coherent joint”, explains the professor.

Industrial production
The pilot phase ended in October of last year. Now Fitafer is preparing itself to commercially produce its first samples during the second semester of this year. Initially it is going to manufacture only pieces of small dimensions, such as sheets for blenders, using the same furnace used to produce the pilot sheets. In order to start up commercial production, a new area of the company is under construction that will be ready in August. The forecast for manufacturing larger sheeting, such as the cover for the sump casing of a motor, is for the end of next year. “We need a larger oven in order to manufacture pieces of larger size, and for this a high investment is necessary”, explains Ecidir Dias Taverneiro, the executive director of the company.

Last year Fitafer’s revenues reached R$ 8 million. When the larger parts are in the process of being produced, potential purchasers will be defined. The automobile industry is one of their strong candidates, as well as the metal stamping companies. However, as Fitafer also has its own stamping presses, it could supply the part itself. “Everything is going to depend on the part size, if it does or does not fit into our press”, anticipates Taverneiro.

The possibilities of the application of the VDS sheets are varied: electrical equipment, construction materials and the automobile industry. This wide field of action is attracting the Brazilian large steel making companies, which have already demonstrated their interest in mastering the process in order to produce the sheeting. In the opinion of Assis, the company Usiminas is investing in research in order to achieve its own technology for producing similar sheeting to VDS. The Companhia Siderúrgica Nacional (CSN), by way of its subsidiary Inal, has already proposed a joint venture to Fitafer for manufacturing the VDS sheeting with the technology developed through the support of the PIPE program. In the meantime, the IPT and the project’s coordinator are studying the request of a patent for the process of the manufacture of the sheeting.

Victorious partnership
For the professor, small companies do not have any way to compete with the large companies, neither in scale or in technology. Consequently, warns Assis Junior, they need to diversify their activities in order to survive. This philosophy is shared by Fitafer which aiming “to adapt its products to the needs of the Brazilian market in steel sheets”.

Now the company has in its hands and important and essential product in the present stage of being industrially developed, in which care about environmental questions is in the front line of fire of productive demands. A product with large commercial prospects, drafted out in an exemplary manner in a partnership between the company, a specialist and with the fundamental help of a century old and recognized research institute.

The project
Development of VDS (Vibration Damping Steel) Sheets, for the Absorption of Sound and Vibration (nº 97/07407-4); Modality Small Business Innovation Research Program (PIPE); Coordinator Francisco de Paula Assis Júnior – Fitafer; Investment R$ 246,700.00